Generally, patients have been provided with prescriptions in one of two ways. One way is to provide prescriptions that are pre-filled in vials ("unit-of-use drugs") at a remote location and kept in inventory at a pharmacy. These unit-of-use drugs are removed from stock when needed and relabeled with patient specific information. Another method involves filling prescriptions by having a pharmacist hand-dispense the required drugs from a bulk supply and then place a patient specific label on a vial.
There are disadvantages to both of these prescription-filling methods. If pharmacists elect to use unit-of-use drugs, they must carry an inventory of several hundred drug types. Furthermore, they must manage inventory levels and monitor stock for expiring products. Generally, a pharmacist will pay a premium for having the drugs pre-packaged.
On the other hand, filling prescriptions from bulk on an individual basis is very labor intensive and subject to human accounting errors. Further, servicing a large patient population requires large numbers of pharmacists.
Automated prescription-filling apparatus are available that count oral solid prescriptions. In one patented device, drugs are stored in bulk storage canisters in rotary dispenser lines that dispense the drugs. Drugs are dispensed from the canisters into vials. The canister is keyed to a specific storage position within such a device by a mechanical pin arrangement. Provisions are made in the event there is an inability to fill a prescription or order. Once filled, all of the patient's prescriptions are collected and made available as a single order.
In another available apparatus, single countable drugs are automatically and repetitively counted. However, there is no provision in this type of apparatus for placing the drugs in vials. Other apparatus fill prescriptions from a supply of unit-of-use drugs.
In the retail pharmacy market, in particular, there is a noted lack of devices that would serve to automate the prescription filling process. The devices described above work well within the limited field of use each afford. However, no products presently on the market can both retrieve, count and dispense a variety of oral solid drugs in the retail setting.
State-of-the-art automated prescription dispensing apparatus possess several disadvantages. These apparatus do not provide for the dispensing of countable drugs and unit-of-use drugs in the same device. These apparatus do not use machine-readable information to identify a canister with a specific location within the apparatus, thus assuring the return of a canister to the proper location without operator intervention. These apparatus do not optimize the location of a canister within the apparatus based on the frequency of drug use.